Filter box



FIG. 1 is a front perspective view showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a back view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is an enlarged perspective view of the section in FIG. 1.

The broken lines in the drawings depict portions of the filter box that form no part of the claimed design. 

CLAIM The ornamental design for a filter box, as shown and described. 